Photoionization of temperature-controlled nanoparticles
A high-precision approach for extracting ionization energies and work functions from free nanoparticles in a beam.
From beam to threshold
Alkali-metal nanoparticles are generated by gas aggregation, thermally equilibrated in a temperature-controlled tube, and ionized with wavelength-selected light. A time-of-flight mass spectrometer characterizes the particle-size distribution, while normalized ion yields are fitted using Fowler theory.
The Review of Scientific Instruments paper reports approximately 0.2% precision in work-function determination, enabled by source stability, automated scans, photon-flux normalization, and finite-size corrections.
Instrumentation includes cryogenic thermalization, ultraviolet optics, ion detection, Arduino motion control, LabVIEW automation, and quantitative data analysis.